'86 300SDL transmission quesiton

My transmission is acting strange. The car shifts very hard at very low rpm. Under mid to full throttle from a standing start, it feels like it shifts 'normally'.
Also, I'm hearing alot of noise (obove the normal roar of the diesel). I can't tell if it's from the rear end or the transmission.
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Kevin L. Bray
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Your car has a vacuum leak or disconnected vacuum line. The transmission's shifts are modulated by vacuum that's controlled by a vacuum valve attached to the throttle linkage. The MORE the throttle is opened the LESS vacuum is sent to the transmission's modulator. Light throttle lots of vacuum, full throttle no vacuum.
Check the vacuum lines to and from the white? plastic valve that's attached to the injection pump - at least it is on the 5 cylinder engines, your six probably similar.
Noise is very subjective, fix the vacuum and then look underneath for the noise. perhaps it's an exhaust leak.
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